/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.idc.common.util;

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class SecureRandomUtils {

	private static SecureRandom SECURE_RANDOM;
	static {
		try {
			SECURE_RANDOM = SecureRandom.getInstance("SHA1PRNG");
		} catch (NoSuchAlgorithmException e) {
			SECURE_RANDOM = new SecureRandom();
		}
	}

	public static SecureRandom getInstance() {
		return SECURE_RANDOM;
	}

	public static String randomNumeric(int num) {
		StringBuilder numBuilder = new StringBuilder();
		for (int i = 0; i < num; i++) {
			numBuilder.append(SECURE_RANDOM.nextInt(10));
		}
		return numBuilder.toString();
	}

}
